A thermotropic liquid-crystalline polymer (which is hereinafter abbreviated to “LCP”) has good properties, including heat resistance, mechanical properties such as rigidity, chemical resistance and dimensional accuracy. Owing to those properties, LCPs are used not only for manufacturing molded articles but also for a variety of products including fibers and film. In the information and telecommunication fields, very thin parts are sometimes required. Personal computers and mobile phones in particular employ highly integrated devices and those skilled in the art wish to use downsized, thinner and smaller parts for them. Because of the excellent molding processability of the LCPs, i.e., good flowability and less formation of burrs, consumption of LCPs has been increasing recently.
However, electronic parts used in the information and telecommunication fields are getting thinner and more complex from day to day, and therefore, the art requires further improvement of molding flowability of LCPs.
A wide variety of methods for improving the molding flowability of LCPs have been proposed. For example, Patent document 1 discloses a method for producing an LCP resin composition having improved fluidity which comprises blending liquid-crystalline polymers having specific molecular weights. Patent document 2 discloses a method for producing an LCP resin composition improved in terms of fluidity which comprises admixing an oligomer of 4-hydroxybenzoic acid having a specific flow temperature into a liquid-crystalline polymer. Patent document 3 discloses a method for producing a liquid-crystalline resin having excellent fluidity by means of a melt polymerization reaction involving acetic acid elimination wherein the reaction liquid is sent to and passed through a vertical stirring thin-film evaporator to decrease acetic acid generation by the liquid-crystalline resin thus obtained. Patent document 4 discloses a method for producing a liquid-crystalline polymer having improved fluidity which comprises adding a phosphoric acid-based compound to the reaction system.
However, the methods disclosed in Patent documents 1 and 2 are problematic in that the manufacture of the liquid-crystalline polymers having specific molecular weights, and in that the manufacture of the oligomer of 4-hydroxybenzoic acid having the specific flow temperature is not easy. The method disclosed in Patent document 3 is problematic in that it requires the use of specialized equipment such as a vertical stirring thin-film evaporator. The method disclosed in Patent document 4 is problematic in that there is significant impairment of mechanical properties of the liquid-crystalline polymer depending on the type and amount of the phosphoric acid-based compound used.
In view of the problems in the above-mentioned methods, those skilled in the art wish to develop an LCP composition which exhibits improved molding flowability without impairing its mechanical properties and which can be produced from inexpensive and easily available materials without the use of specialized equipment.    [Patent document 1] Japanese Patent Application Laid Open No. Hei 2-173156 corresponding to U.S. Pat. No. 5,766,507    [Patent document 2] Japanese Patent Application Laid Open No. Hei 3-095260 corresponding to U.S. Pat. No. 5,352,746    [Patent document 3] Japanese Patent Application Laid Open No. 2000-309636    [Patent document 4] Japanese Patent Application Laid Open No. Hei 06-032880